Some bis(halomethyl)-phosphorylmethyltriphenylphosphonium halides and a stable phosphine methylene

ABSTRACT

The 1:1 triphenylphosphine adducts of tris(chloromethyl)phosphine oxide, tris(bromomethyl)phosphine oxide, and tris(iodomethyl)phosphine oxide were prepared. The chloro derivative was converted to triphenylphosphine bis(chloromethyl)phosphorylmethylene by reaction with aqueous ammonium hydroxide. These phosphorus compounds are useful as flame retardants for cellulosic materials.

United States Patent Donald J. Daigle New Orleans;

Leon H. Chance, New Orleans; George L. Drake, Jr., Metairie, all of La.

Aug. 29, 1969 Sept. 21,1971

The United States of America as represented by the Secretary of Agriculture Inventors Appl. No. Filed Patented Assignee SOME BIS(HALOMETHYL)- PHOSPHORYLME THYLTRIPHENYLPHOSPHONIUM HALIDES AND A STABLE PHOSPHINE METHYLENE 6 Claims, No Drawings U.S. Cl ..260/606.5 F, 25 2/8. 1 int. Cl C07f 9/54, C09k 3/28 Field of Search 260/6065 [56] References Cited UNITED STATES PATENTS 3,426,073 2/1969 Birum et all .7 260/6065 F 3,445,570 5/1969 Birum et a1. 260/6065 F 3,524,886 8/1970 Fried 260/6065 F Primary Examiner Tobias E. Levow Assistant Examiner-Werten F. W. Bellamy Atmrneys-R. Hoffman and W. Bier ABSTRACT: The l:l triphenylphosphine adducts of tris(chl0romethyl)phosphine oxide, tris(bromomethyl)phosphine oxide, and tris(i0domethyl)phosphine oxide were prepared. The chloro derivative was converted to triphenylphosphine bis(chloromethyl)phosphorylmethylene by reaction with aqueous ammonium hydroxide. These phosphorus compounds are useful as flame retardants for cellulosic materials.

SOME BIS(HALOMETHYL)- PHOSPHORYLMETHYLTRIPHENYLPHOSPHONIUM HALIDES AND A STABLE PHOSPHINE METHYLENE A nonexclusive, irrevocable, royalty-free license in the invention herein described, throughout theworld for all purposes of the United States Government, with the power to grant sublicenses for such purposes is hereby granted to the Government of the United States of America.

This invention relates to the triphenylphosphine;adducts of haloalkyl phosphine oxides and to phosphine methylenes derived therefrom, which are useful as flame retardants for cellulosic textiles. More specifically, this invention relates to some new bis(halomethyl)phosphorylmethyltriphenylphosphonium halides, to new stable triphenylphosphine bis(halomethyl)phosphorylmethylenes, and to methods of their preparation.

The main object of the instant invention is to disclose the new phosphonium halide types produced by processes of the instant invention.

A second object of the instant invention is to disclose a new stable phosphine methylene produced by processes of the instant invention.

Searching the prior art we find that the simplest process for the preparation of phosphonium halides is conducted by reacting an alkyl halide with a tertiary phosphine oxide [Kosolapoff, G. M., Organophosphorus Compounds, John Wiley and Sons, Inc., New York, p. 78 (1950)]. The phosphonium halides of the present invention differ from those of the prior art in that haloalkylphosphine oxides are employed rather than simple alkyl halides. Thus the phosphonium halides of the present invention are of a new 1; e.

in the course of the investigation we have found that phosphonium halides having the graphic formula where X represents a halogen, can be prepared by reacting triphenyl phosphine with tris(chlromethyl)phosphine oxides having the graphic formula where X is a halogen.

We have also found that only when X is chlorine in phosphonium halides of the graphic formula does one obtain a phosphine methylene of the formula when the phosphonium halide is treated with a base. When-X is bromine or iodine the phosphine methylene is not obtained.

We have also found that a compound containing mixed halogens, viz, bis(chloromethyl)phosphorylmethyltriphenylphosphonium bromide, can be prepared by the reaction of triphenylphosphinebis(chloromethyl)phosphorylmethylene with bromine.

In accordance with the present invention the reaction of triphenylphosphine with tris(halomethyl)phosphine oxides is carried out by heating the two reactants in an appropriate solvent. The solvent may be a nonpolar solvent such as benzene or a polar solvent such as isobutyl alcohol. The preferred solvent for the chloromethyl and bromomethyl phosphine oxides is benzene, and for the iodomethyl phosphine oxide, isobutyl alcohol. The preferred reaction temperatures are the reflux temperatures of the particular solvent. The phosphonium halide products were identified by infrared and proton magnetic resonance spectra,'by formation of picrate derivatives, and by elemental analyses. I i

In accordance with the present invention triphenylphosphinebis(chloromethyl)phosphorylmethylene was prepared by reaction of bis(chloromethyl)phosphorylmethyl tripheylphosphonium chloride with an aqueous base. The preferred base is ammonium hydroxide.

The phosphonium halides are useful as flame retardants for cellulosic materials and also as intermediates to other chemical compounds. Cotton fabric was made flame retardant by impregnating the fabric with a 1'5 percent aqueous solution of the phosphonium halides and drying the fabric. The concentration of the flame retardant may be varied above or below 15 percent depending on the degree of flame retardancy desired.

The following examples illustrate the methods of carrying out the invention, and are included for purposes of illustration, not as a limitation thereof.

EXAMPLE 1 Preparation of Bis(chloromethyl)phosphorylmethyltriphenylphosphonium chloride (1) v Tris(chloromethyl)phosphine oxide (3.0 grams, 0.0153 mole) was refluxed with triphenylphosphine (4.19 grams, 0.016 mole) in benzene for 18 hours. The resulting solution was filtered and yielded 5.8 grams (83 percent yield) of crude product. Recrystallization of I from methanol-benzene yielded a pure product, m.p. 230-231.5 C.

Anal. calcd. for C H CI OP C, 55.11; H, 4.63; cl. 23.24; P, 13.29. Found: C, 55.45; H, 4.86; CI, 22.72; P, 13.29.

The picrate of! had a melting point of l64.5-66 C. Anal. calcd. for C ,l -l Cl N O P N, 6.46; CI, 10.90; P, 9.52. Found: N, 6.40;C1,. 10.63; P, 9.02.

EXAMPLE 2 Preparation of Bis(chromomethyl)phosphorylmethyltriphenylphosphonium bromide (11) The same procedure as that used for the preparation of 1, example 1, was followed to produce an 87 percent yield of crude 11. Pure white crystals, m.p. 226-228 C., were obtained by recrystallization from a methanol-benzene mixture.

Anal. calcd. for c n s or z C, 42.67; H, 3.58; Br, 40.56, P, 10.48. Foundf C, 44.1 1; H,4.14; Br, 39.45; P, 10.53.

The picrate of 11 had a melting point of 1823.5 C. Anal. calcd. for C H Br N 0,P N, 5.68; Br, 21.61; P, 8.38. Found: N, 5.44; Br, 20.32; P, 8.08.

EXAMPLE 3 Preparation of Bis(iodomethyl)phosphorylmethyltriphenylphosphonium iodide (III) The same procedure as that used for the preparation of 1,

example 1, was followed except isobutyl alcohol was used as the solvent. An percent yield of crude white crystals was obtained, m.p. 228-229 C. after recrystallization from water.

Anal. calcd. for C H J OP C, 34.45; H, 2.89; l, 52.00; P, 8.46. Found: C, 34.98; H, 3.12; I, 52.13; P, 8.26. The picrate of 111 had amel ting point of l67-8 C. Anal. calcd. for C l-1 1 =,N,O-,P N, 5.04; l, 30.46; P, 7.43, Found: N, 4.85; l, 30.16; P, 7.13.

EXAMPLE 4 Preparation of Triphenylphosphinebis(chloromethy l)phosphorylmethylene (1V) 1 (2.5 g. 0.00546 mole) was dissolved in 75 ml. of water. Upon the addition of 75 ml. of a 2 percent aqueous ammonium hydroxide solution, a thick oily substance separated, which with shaking eventually turned into a white solid. The yield of crude IV was 1.42 g. (62 percent). White crystals, m.p. 12930 C., were obtained by recrystallization from benzene-hexane. Anal. calcd. for C H CI OP C, 59.71; H, 4.73; CI, 16.82; P, 14.69. Found: C, 59.30; H, 4.66; CI, 16.28; P, 14.59.

EXAMPLE 5 Preparation of Bis(chloromethyl)phosphorylmethyltriphenylphosphonium Bromide (V) IV (0.5 g., 0.00119 moles) was dissolved in 50 ml. of methylene chloride and a bromine solution of methylene chloride added until a slight orange color persisted. Evaporation of the solvent gave a semisolid which was dissolved in either methanol or methylene chloride and benzene added until the solution became cloudy. A white compound weighing 0.42 g. (70 percent) was obtained, m.p. 225-7 C.

Anal. calcd. for C ,l-l BrC1 OP C, 50.20; H, 4.18; Br, 15.94; P, 12.35. Found: C, 50.36; H,4.25;P, 12.28; Br, 16.65.

EXAMPLE 6 Fabric Treatment A water solution containing 15 percent by weight of bis (chloromethyl) phosphorylmethyltriphenylphosphonium chloride was applied to 8 02. cotton sateen fabric by passing through squeeze rolls to an 80 percent wet pickup and drying for 5 minutes at 80 C. The fabric had a 12 percent weight gain and was flame retardant.

Fabric was made flame retardant in a similar manner with the bromoand iodo-analogs.

The fabric treatments were evaluated by a well known rapid evaluation flame retardancy test which consists of cutting a small specimen (about 1 cm. X 7 cm.) of the fabric to be evaluated, placing the specimen above the flame of a kitchen match with the long axis of the fabric specimen at an angle of to the flame, igniting the specimen (if it can ignite), removing the flaming specimen from the flame, and rotating the specimen until the flame is extinguished, and recording that angle. (The 0 angle would be where the flame is at the top of the specimen, and the most severe test would be where the flame would be at the bottom. This would be the 180 angle.)

The specimens of example 6 did not support combustion upon being submitted to this rapid evaluation test; therefore, they passed the flame retardancy test.

We claim:

1. Compounds of the graphic formula where X is a halogen.

2. Bis(chloromethyl)phosphorylmethyltriphenylphosphonium chloride.

3. Bis(bromomethyl)phosphorylmethyltriphenylphosphonium bromide.

4. Bis(iodomethyl)phosphorylmethyltriphenylphosphonium iodide.

5. Bis(chloromethyl)phosphorylmethyltriphenylphosphonium bromide.

6. Triphenylphosphinebis(chloromethyl)phosphorylmethylene. 

2. Bis(chloromethyl)phosphorylmethyltriphenylphosphonium chloride.
 3. Bis(bromomethyl)phosphorylmethyltriphenylphosphonium bromide.
 4. Bis(iodomethyl)phosphorylmethyltriphenylphosphonium iodide.
 5. Bis(chloromethyl)phosphorylmethyltriphenylphosphonium bromide.
 6. Triphenylphosphinebis(chloromethyl)phosphorylmethylene. 